1. Field of the Invention
This invention relates to carpet backsizing, and more particularly it relates to hot melt backsizing compositions which result in carpets having high tuft bind.
2. Description of the Prior Art
Backsizing of tufted carpets with hot melt backsize adhesives has been known now for some years. U.S. Pat. No. 3,551,231 discloses a process for applying a hot melt backsize adhesive blend of ethylene/vinyl ester copolymer, petroleum wax, and a thermoplastic resin. Satisfactory carpets are made by applying a critical pressure on the tufted structure while it is in contact with the hot melt adhesive applicator roll. The necessity of maintaining such critical pressure during the adhesive application detracts from process flexibility.
U.S. Pat. No. 3,684,600 discloses the application of a low viscosity precoat adhesive to the backside of the tufted structure prior to the application of the hot melt backsize adhesive composition. By using the precoat adhesive, the necessity of maintaining a critical pressure on the carpet during the hot melt adhesive application can be eliminated. The backsize adhesive composition contains ethylene/vinyl ester copolymer, low molecular weight, low density polyethylene, microcrystalline wax, aliphatic thermoplastic hydrocarbon resin, dicyclopentadiene alkylation polymer, antioxidant and filler.
U.S. Pat. No. 3,583,936 discloses a hot melt backsize adhesive composition comprising an ethylene/vinyl ester or acrylate polymer, a wax of sufficiently high melting point to yield a blend softening point of at least 190.degree. F., a blend of aliphatic thermoplastic hydrocarbon resin and a dicyclopentadiene alkylation polymer, and optionally a filler.
U.S. Pat. No. 3,745,054 relates to high filler content hot melt backsize adhesive compositions comprising ethylene/vinyl ester copolymer, paraffin wax, microcrystalline wax, aliphatic thermoplastic hydrocarbon resin, dicyclopentadiene alkylation polymer, antioxidant and filler.
Previously, filler containing hot melt blends have been used to produce carpets having tuft binds which generally average in the 6 to 10 lb. range. While this is generally adequate for domestic carpet (used in the home), higher tuft bind values will ensure greater durability. Considerably higher tuft binds (18 lb. average or greater), which up to the present has not been attainable, are desired by the carpet industry for contract carpet (used in schools, hotels, churches, industry, etc.) to ensure meeting typically severe service requirements.